spi-topcliff-pch: Fix overrun issue

[pandora-kernel.git] / mm / memcontrol.c

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f4ec4e7..ebd1e86 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1841,29 +1841,23 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
  */
 static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
 {
-       int lock_count = -1;
        struct mem_cgroup *iter, *failed = NULL;
        bool cond = true;
 
        for_each_mem_cgroup_tree_cond(iter, mem, cond) {
-               bool locked = iter->oom_lock;
-
-               iter->oom_lock = true;
-               if (lock_count == -1)
-                       lock_count = iter->oom_lock;
-               else if (lock_count != locked) {
+               if (iter->oom_lock) {
                        /*
                         * this subtree of our hierarchy is already locked
                         * so we cannot give a lock.
                         */
-                       lock_count = 0;
                        failed = iter;
                        cond = false;
-               }
+               } else
+                       iter->oom_lock = true;
        }
 
        if (!failed)
-               goto done;
+               return true;
 
        /*
         * OK, we failed to lock the whole subtree so we have to clean up
@@ -1877,8 +1871,7 @@ static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
                }
                iter->oom_lock = false;
        }
-done:
-       return lock_count;
+       return false;
 }
 
 /*
@@ -2091,6 +2084,7 @@ struct memcg_stock_pcp {
 #define FLUSHING_CACHED_CHARGE (0)
 };
 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
+static DEFINE_MUTEX(percpu_charge_mutex);
 
 /*
  * Try to consume stocked charge on this cpu. If success, one page is consumed
@@ -2168,13 +2162,7 @@ static void drain_all_stock(struct mem_cgroup *root_mem, bool sync)
 
        /* Notify other cpus that system-wide "drain" is running */
        get_online_cpus();
-       /*
-        * Get a hint for avoiding draining charges on the current cpu,
-        * which must be exhausted by our charging.  It is not required that
-        * this be a precise check, so we use raw_smp_processor_id() instead of
-        * getcpu()/putcpu().
-        */
-       curcpu = raw_smp_processor_id();
+       curcpu = get_cpu();
        for_each_online_cpu(cpu) {
                struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
                struct mem_cgroup *mem;
@@ -2191,14 +2179,14 @@ static void drain_all_stock(struct mem_cgroup *root_mem, bool sync)
                                schedule_work_on(cpu, &stock->work);
                }
        }
+       put_cpu();
 
        if (!sync)
                goto out;
 
        for_each_online_cpu(cpu) {
                struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
-               if (mem_cgroup_same_or_subtree(root_mem, stock->cached) &&
-                               test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
+               if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
                        flush_work(&stock->work);
        }
 out:
@@ -2213,14 +2201,22 @@ out:
  */
 static void drain_all_stock_async(struct mem_cgroup *root_mem)
 {
+       /*
+        * If someone calls draining, avoid adding more kworker runs.
+        */
+       if (!mutex_trylock(&percpu_charge_mutex))
+               return;
        drain_all_stock(root_mem, false);
+       mutex_unlock(&percpu_charge_mutex);
 }
 
 /* This is a synchronous drain interface. */
 static void drain_all_stock_sync(struct mem_cgroup *root_mem)
 {
        /* called when force_empty is called */
+       mutex_lock(&percpu_charge_mutex);
        drain_all_stock(root_mem, true);
+       mutex_unlock(&percpu_charge_mutex);
 }
 
 /*